1. Field of the Invention
The present invention is broadly concerned with a composite roof structure, and a method of forming the same, wherein use is made of an adhesive adapted to be secured to a roof substrate, along with an upper, flexible membrane comprising a sheet of flexible rubber-like material with fleece-like matting secured to the underside thereof. In practice, a relatively slow-setting polyurethane foam adhesive is employed, with an EPDM rubber membrane having a polyester matting secured thereto. In application procedures, the adhesive is sprayed onto a properly prepared roof substrate and, prior to complete solidification of the adhesive, the flexible membrane is applied so that the matting becomes at least partially embedded within the adhesive. Upon complete adhesive solidification, the membrane is secured in place, with a vapor venting spacing being provided between the adhesive material and rubber-like sheet.
2. Description of the Prior Art
Many different roofing systems have been proposed in the past, ranging from simple asphalt/gravel roofs to more sophisticated structures making use of synthetic resin materials such as polyurethanes. Roofs fabricated using foamed materials have presented problems because of the fact that the foams tend to set up and solidify almost immediately, thereby making it difficult to properly bond membranes or other materials thereto.
It has also been known in the past to construct roofs using synthetic rubber membranes formed from EPDM rubber. In such constructions, asphalt or other adhesive substance is first applied to a substrate, followed by an attempt to directly adhere the EPDM rubber to the adhesive. In the first place, it is very difficult to properly bond the EPDM rubber directly with an adhesive, and accordingly the resultant roof is subject to wind uplifts. Secondly, such a construction provides little if any vapor ventilation capabilities, and thus such roofs are often prone to excessive blistering.